Threaded insert with prongs extending from an end flange



1 j P. D. BECKER ET AL 2,818,901

THREADED INSERTEWITH PRONGS EXTENDING FROM AN END FLANGE Filed Nov. 10,1954 2 Sheets-sheaf 1 \NvENToRs;

PHHJP D. BECKER, v HENRM 8, Jon NSEN, WW?

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Jan"; 1958 P. D. BECKER; ET AL 2,818,901

THREADED INSERT WITH PRONGS EXTENDING FROM AN END FLANGE Filed Nov. 10',1954 Y 2 Sheets-Sheet 2 FacafZ F168.

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THREADED INSERT WITH PRONGS EXTENDING FROM AN END FLANGE Philip D.Becker, Hingham, and Henrik S. Johnsen, Medford, Mass., assignors, bymesne assignments, to United- Carr Fastener Corporation, Boston, Mass.,a corporation of Delaware Application November 10, 1954, Serial No.467,924

1 Claim. (Cl. 151-41.73)

This invention relates generally to fastening devices and has particularreference to a device for attachment to a panel to receive a cooperatingfastener member.

111 the manufacture of certain types of flanged fastening devices, suchas flanged nuts having a drawn threaded barrel, it has been desirable toform prongs from the flange to enable the device to be attached to apiece of wood or similar material.

Such devices are satisfactory for many applications, but in some casesit is desirable to provide prongs of greater length than has heretoforebeen practical, and in some cases it has been found that the prongscause splitting of the wood during attachment.

It has heretofore been customary to provide longer prongs by increasingthe dimensions of the flange from which the prongs are formed; however,this requires a wider strip of metal to form the larger flange andconsequently increases the amount of scrap and the cost of the device.Longer prongs, so formed, also have the disadvantage that they tend tobreak at the junction with the flange, where the amount of working ofthe metal during forming is greatest and where the bending is greatest,which requires that the prongs be considerably widened at this point.However, prongs so widened have a greater tendency to cause splitting ofthe wood during attachment.

The object of the invention is to provide a flanged fastening devicehaving prongs of suitable length formed from the flange in a mannerrequiring a minimum size of flange.

A further object of the invention is to provide a flanged fasteningdevice having prongs formed from the flange in which means is providedto resist breaking of the prongs at the junction with the flange.

Other objects of the invention will, in part, be obvious, and will, inpart, appear hereinafter.

In the drawing:

Fig. 1 is a top plan view of a fastening device embodying the featuresof the invention;

Fig. 2 is a view in side elevation of the fastener of Fig. 1;

Fig. 3 is a bottom plan view of the fastener of Fig. 1 assembled with asupport panel;

Fig. 4 is a view in section taken on line 4--4 of Fig. 3;

Fig. 5 is a top plan view of a die used in forming the prongs from theflange;

Fig. 6 is a view in transverse section of a punch for use with the dieof Fig. 5;

Fig. 7 is a view in transverse section of the assembled punch and die ofFigs. 5 and 6 during the initial step of shearing the prongs from theflange;

Fig. 8 is a view in section taken on line 88 of Fig. 7;

Fig. 9 is a view in transverse section of the punch and die after thecompletion of the prong forming operation; and

Fig. 10 is a view in section taken on line 10-10 of Fig. 9.

eferring to the drawing, there is illustrated a fastenited States Patent0 2,818,901 Patented Jan. 7, 1958 ing device 10 of the type commonlyknown as a flanged nut, which comprises a drawn barrel 12 having anmternal aperture 14 threaded to receive a bolt and an attachrng flange18 disposed at one end of the barrel.

To permit attachment of the device 10 to a panel 20, a series of prongs22 are formed in the outer periphery of the flange and are bent toextend substantially perpendicular thereto.

The prongs 22 are formed by a shear 24 which initiates at a point 25spaced inwardly from the periphery and extends on an are generallycircumferentially and progressing gradually radially outwardly. In theillustrated embodiment the are along which the shear extends has aradius R1 which is approximately the same as the radius R2 of theflange, and the center C1 of the arc is offset from the center C2 of theflange so that the arc' intersects the periphery of the flange in such amanner as to provide a tapered end portion terminating in a sharppoint26.

To assist in the forming of the prongs in a manner to appear hereinafterand to prevent the tendency of the prongs to break at the junction withthe base during at tachment, an embossed circular groove 27 is providedin the flange which passes through the initial points 25 at the insideedge of the prongs.

The preferred method of forming the prongs is best illustrated byreference to Figs. 5 through 10 in which is shown a die 28 and a punch30 which have cooperating shearing edges 32 and 34. The shearing edges32 of the die progress circumferentially and inwardly and terminate at arounded bending nose 36 which extends generally radially.

To form the prongs, the flanged nut is placed on the die, and the punchdriven down onto the flange to force it through the die, shearing theflange along the cutting edges (see Figs. 7 and 8). As the punch isforced down further, the rounded nose 36 bends the prongs upwardly, andin doing so, tends to tear the metal at the base of the prong. Suchtearing usually proceeds a distance about equal to the thickness of themetal of which the flange is formed. To insure that such tearing willproceed in the proper direction, that is circumferentially, and will nottend to extend across the base of the prong, the embossed circulargroove 27 is provided in a suitable position to be at the inside edge ofthe junction of the prong with the base, so that the flange will tearalong the line of weakness provided by the groove. As the punch isforced downwardly, the ends of the prongs, in turning upwardly, rideagainst the outer surface of the punch so that they are at leastpartially straightened. It has been found advantageous to stop the punchbefore the prongs are completely straightened, so that after completionof the operation, the prongs are curved slightly inwardly and I alsoslightly circumferentially (see Fig. 10). This structure has been founddesirable for controlling the direction the prongs travel when beingdriven through a panel.

The method of forming of the prongs illustrated and describedhereinbefore is particularly advantageous in cases where it is desiredto secure a nut to a relatively thin piece of wood, without the barrelprotruding therefrom. In such cases a relatively short barrel isrequired with long thin prongs for piercing completely through the woodwithout causing splitting.

As illustrated in Fig. 4, the fastener may be secured to a piece of wood40 having an aperture 42 extending therethrough by driving the prongsthrough the wood and curling the ends over on the opposite side thereof,with the barrel 12 being disposed in the aperture 42. If desired, :1prong positioning groove 44 may be provided about the aperture 42 toinsure that the barrel is properly positioned to enter the aperture.

In the illustrated embodiment the groove extends completely around thetflange sin ce it is convenient to form the prongs in a secondaryoperation after the forming of the nut, without the necessity oforienting the nut in the die. However, it will be obvious that in somecases the ,embossedgroove need he formed in the flange only at the,egract positions needed. Although the illustrated embodiment utilizesthree prongs, this is exemplary .only sinceother numbers may he used.

Sinc ce t in oth r obvious modifications .may he made in th devieewi honsdepar ing from the scope ,of the in.- ntien, i intended tha all mattercontained herein be interpreted in an illustrative and not in a limitingsense.

We claim:

A fastening de /ice for attachment to a panel -.to receive a cooperativefastener element comprising a center hrea ed as ne portion, an att chingflange disposed b u t e fas en por on and being substantiall perpend ela t th axis o the ta t n r po tion, a series of atta hin pr n ext nd ngsubstant ally p rp n i ular rom t e pl n pf t e flange sai p ong h beingformed from the periphery of the flange by a shearextendinggenerally.circumferentially and progressing gradually radiallyoutwardly therefrom to intersect the outer periphery of the flange andto form an arcuate portion, and a circumferential groove in said flangeand disposed at the inside edge of the base of the prongs intersectingthe ends of the shear whereby stresses occurring at the base of theprongs are directed circumferentially.

R fe ence Ci in he file of this P t nt UNITED STATES PATENTS 1,493,501Rice May 13, 1924 2,102,558 Johnson Dec. 14, 1937 2,108,399 Allen .1Feb. 15, 1938 2,284,081 Beggs May 26, 1942 FOREIGN PATENTS 11 6 ,35, 6Great Britain June 11, 1918 449,422 Great Britain June 26, 1936

